Scilab Function
Last update : 18/11/2005

TCL_ExistVar - Return %T if a tcl variable exists

### Calling Sequence

  `OK=TCL_ExistVar(varname [,interp])`

### Parameters

- `varname`: character string. Contains the name of the tcl/tk variable.
- `interp`: optional character string parameter. Name of the slave tcl interpreter in which the operation has to be performed. If not provided, it defaults to the main tcl interpreter created by Scilab.
- `ok`: boolean. %T if varname exists.

### Description

This routine allows to test if a tcl variable exists.

### Examples

    TCL_SetVar("Scilab","OK")
    TCL_GetVar("Scilab")
    TCL_UnsetVar("Scilab")
    TCL_ExistVar("Scilab")

    TCL_SetVar("aa",1)
    TCL_CreateSlave('SlaveInterp');
    TCL_SetVar("aa",2,'SlaveInterp')
    TCL_ExistVar("aa")
    TCL_GetVar("aa")
    TCL_UnsetVar("aa")
    TCL_GetVar("aa",'SlaveInterp')
    TCL_UnsetVar("aa",'SlaveInterp')
    TCL_ExistVar("aa",'SlaveInterp')
    TCL_DeleteInterp('SlaveInterp')

### See Also

`ScilabEval`, `TCL_EvalFile`, `TCL_EvalStr`, `TCL_GetVar`, `TCL_SetVar`, `TCL_UnsetVar`, `TCL_UpVar`, `TCL_CreateSlave`,

### Author

Allan CORNET